Radio communication systems define radio channels upon data is communicated between a set of communication devices. Because data is communicated upon radio channels, rather than channels defined upon wirelines, communication of data is possible without the need to interconnect the communication devices of the set by way of fixed connections.
Communication of the data upon the radio channels is, however, sometimes challenging as the radio channels, defined upon a portion of the electromagnetic spectrum, are non-ideal, i.e., are susceptible to noise, fading, and other distortion. If severe, the data, when received at a receiving communication device might be distorted to an extent that the informational content of the received data can not be recovered.
Significant attention and effort is directed towards providing manners by which to overcome, and compensate for, the non-ideal nature of the radio channel upon which the data is communicated.
Transmit diversity is, for instance, sometimes used to introduce time redundancy upon the data prior to its communication upon the radio channel. Time redundancy introduced upon the data makes more likely its recovery even if portions of the communication data are significantly distorted. That is to say, by increasing the time redundancy of the data, the likelihood of its loss is reduced, particularly when the distortion introduced upon the data during its communication is time-varying.
Data coding techniques are amongst the techniques by which to introduce transmit diversity upon the data prior to its communication. Various types of coding schemes have been developed and are regularly utilized during communication operations to introduce the time redundancy upon the data. Block coding techniques and convolutional coding techniques are too general categories of coding techniques that are commonly utilized. As the codes are typically used to facilitate the correction of errors introduced upon the data during its communication, the codes are sometimes referred to as being error control codes.
Convolutional codes, in general, operate upon an input data stream and encode the input data into code words, formed of encoded bits. The encoded bits of the code word include both convolved bits and nonconvolved bits. That is to say, the encoded bits of the code words depend not only on current input bits but also on past input bits.
The performance of a code, or technique by which to form the code, is characterized, at least in part, by its so-called distance property. An error control code that exhibits good performance tends, generally, to have large spacings, or distances, between code words that are formable by the code. The distance property permits a decoder, oftentimes a Viterbi decoder, to be constructed at a receiving communication device that attempts to identify the most likely transmitted code word by finding the code word that is nearest to a received sequence of data. Generally, the larger the distance between the code words, the greater the number of errors that can be tolerated in the transmission of the data while still permitting the data successfully to be decoded, thereby to recover the informational content of the data.
Standardization of communication protocols related to ultra wide band (UWB) orthogonal frequency division multiplex (OFDM) communications systems is ongoing. Data communications over wide bandwidths in such type of system, over short ranges, is, e.g., contemplated. A variant of the IEEE 802 family of communication standards, such as the IEEE 802.15.3a operating specification is undergoing standardization.
Ultra wide band transmission procedures, protocols and parameters are set forth in the operating specification. Included amongst the proposals for inclusion in the standardized operating specification are error control codes that achieve various data communication rates.
While the existing error control codes that are presently proposed provide coding gain to help compensate for, or overcome, communication of data upon a non-ideal channel, not all of the codes provide for optimal performance.
In a manner could be provided that would perform better at various code rates, improved communication performance would be possible in a communication system operable in conformity with the operating specification.
It is light of this background information related to communications in a radio communication system that the significant improvements of the present invention have evolved.